Cruise Control Coasting Feedback for Accurate Resistance Estimation
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Solution Overview
Problem
Conventional auto-cruising techniques inaccurately estimate travel resistance, leading to excessive speed drop during coasting and subsequent fuel economy degradation due to fixed resistance coefficients.
Innovation Solution
A travel control device and method that dynamically updates roll and air resistance coefficients based on actual and estimated vehicle speed variations and road grade, using a ratio calculation to refine resistance estimation and maintain optimal speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed resistance coefficients are used for travel resistance estimation, then the control system is simple, but the estimation accuracy deteriorates
Solution Approach 1:
The patent applies the dynamics principle by transitioning from fixed resistance coefficients to dynamically updated coefficients. The control device estimates travel resistance using initially fixed coefficients, then updates these coefficients based on actual vehicle speed variations observed during coasting periods. This dynamic adaptation allows the system to maintain simplicity while improving estimation accuracy through real-time learning of actual resistance conditions.
Solution Approach 2:
The patent implements feedback by using actual vehicle speed variations during coasting to correct the resistance coefficient estimates. The system compares estimated speed variations (based on fixed coefficients) with actual observed variations, calculates the difference, and uses this feedback to update the resistance coefficients. This closed-loop feedback mechanism enables continuous improvement of estimation accuracy without significantly increasing system complexity.
2Device complexity
If fixed resistance coefficients are used, then the control algorithm is simple, but fuel economy deteriorates due to inaccurate estimation
Solution Approach 1:
The patent applies preliminary action by performing coasting maneuvers at specific points (before crests of upslopes) to gather data for updating resistance coefficients before critical fuel-consuming operations. By proactively collecting accurate resistance data during coasting periods and updating coefficients in advance, the system optimizes subsequent acceleration and cruising operations, thereby improving overall fuel economy without requiring complex real-time control algorithms.
Solution Approach 2:
The system uses feedback from actual vehicle performance during coasting to continuously refine resistance coefficient estimates. This feedback loop enables the control algorithm to adapt to actual road conditions, vehicle load variations, and environmental factors, leading to more accurate fuel consumption predictions and optimized control decisions that improve fuel economy while maintaining algorithmic simplicity.
3Device complexity
If fixed resistance coefficients are used, then the system is easy to implement, but speed control accuracy deteriorates during coasting
Solution Approach 1:
The patent implements dynamics by making resistance coefficients adaptive rather than static. During coasting operations, the system dynamically updates coefficients based on actual observed vehicle deceleration patterns. This dynamic adjustment ensures that speed predictions and control decisions during coasting are based on accurate, real-time resistance data, significantly improving speed control accuracy while keeping the implementation approach straightforward and building upon the existing fixed-coefficient system.
Data Source
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AI summary
This cruise control device enables more accurate prediction of running resistance and prevents worsening of fuel economy. In this device, a coasting prediction unit (12c) of an automatic cruise control device (12), which is for performing cruise control of the vehicle (1) on the basis of a resistance coefficient, predicts, on the basis of the resistance coefficient, the change in vehicle speed if the vehicle (1) were to coast; if the vehicle (1) does coast, a vehicle information acquisition unit (12b) acquires information about the detected vehicle speed; and a running resistance updating unit (12f) updates the value of the resistance coefficient on the basis of the information about the change in vehicle speed predicted by the coasting prediction unit (12c) and information about the vehicle speed acquired by the vehicle information acquisition unit (12b).